Harmonic generation in organic dye vapors

Investigations of nonlinear optical frequency conversion of Nd:YAG laser ra diation in naphthalene vapors are presented. The third harmonic generation (THG) caused by difference frequency generation in six-photon process has b een studied. Phase-matching temperature for naphthalene vapor was found to be 170 degrees C, at which synchronous conversion of pump radiation to the third harmonic was carried out. The THG conversion efficiency varied within 10(-10)-10(-8) depending on pump intensity and cell temperature. Third- an d fifth-order nonlinear optical susceptibilities were calculated and compar ed with the experimentally measured fifth-order susceptibility of naphthale ne vapors. (C) 2000 Published by Elsevier Science B.V.